Manufacturing operations in many fields typically require accurate positioning of manufacturing tools over a workpiece. The manufacturing environment and the structural details of the workpiece often make it difficult to properly position the manufacturing tool relative to the workpiece to achieve the desired manufacturing operation with the necessary degree of accuracy. This is particularly true in the field of aircraft manufacturing, wherein a large number of manufacturing operations are typically needed on a variety of contoured surfaces. Similar difficulties may be encountered, for example, in the manufacture of ships, railcars, missiles, sheet metal buildings, and other similar structures.
It is known that a support assembly that supports a manufacturing tool may be temporarily attached to a surface of the workpiece in order to facilitate manufacturing operations on the workpiece. Some conventional support assemblies utilize one or more elongated rails equipped with vacuum cup assemblies for temporarily attaching the support assembly to the workpiece, including, for example, those assemblies generally disclosed in U.S. Pat. No. 6,467,385 B1 issued to Buttrick et al., and U.S. Pat. No. 6,210,084 B1 issued to Banks et al. In such conventional support assemblies, the rails may be coupled to the workpiece using the vacuum cup assemblies over a desired section of the workpiece, and then a manufacturing tool may be mounted on a carriage that is moveable along the rails. The carriage may then be traversed along the rails in a manual or automated fashion, and the desired manufacturing operations may be performed.
Vacuum for the vacuum cup assemblies of such conventional support assemblies is typically generated externally from the point-of-use, such as by a vacuum pump or other suitable source. The vacuum is then routed to each vacuum cup assembly by one or more vacuum lines. In order to isolate one vacuum circuit from another it is usually necessary to run separate, multiple lines to each vacuum cup assembly, or incorporate a valve network to isolate one line from another. Because the pressure differential along the length of each vacuum line is at most one atmosphere, care must be taken to avoid line losses which may degrade the degree of vacuum provided to the vacuum cup assemblies. One conventional approach to solving this line-loss problem is to provide a portable vacuum pump that may be transported along with the vacuum assembly in order to reduce the lengths of the vacuum lines between the vacuum pump and the vacuum cup assemblies.
Traditional hard tooling and indexing systems for large-scale manufacturing operations typically involve the construction of large, “monument like” equipment that provides support and indexing during manufacturing operations on a workpiece. Such structures are typically very expensive to design, build, and maintain. For example, the tooling for a new airplane manufacturing operation may comprise a substantial percentage of the initial investment cost of the manufacturing facilities needed to produce the aircraft.
Although desirable results have been achieved using the prior art manufacturing methods and apparatus, there is still room for improvement. Namely, it may yet be possible to improve the operating efficiency, cost, and performance of such manufacturing operations.